Well water depth monitor

ABSTRACT

Methods, apparatuses, and computer readable medium including computer program products, are provided for determining the depth of water in a well. A method may include coupling a signal onto a cable connected to a submersible well pump. The method may further include monitoring the cable to determine a first time corresponding to a first reflection of the signal caused by the cable entering a water column between a water surface and the submersible pump. The method may further include monitoring the cable to determine a second time corresponding to a second reflection of the signal caused by an impedance mismatch between the cable surrounded by water and a motor in the submersible well pump. The method may further include determining a water height between the submersible pump and the water surface from the first time and the second time.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/684,786 filed on Aug. 23, 2017 and entitled “Well Water DepthMonitor,” which is a continuation of U.S. patent application Ser. No.14/705,880 filed on May 6, 2015 and entitled “Well Water Depth Monitor,”now U.S. Pat. No. 9,784,093, which claims priority to U.S. ProvisionalPatent Application No. 61/990,183 filed on May 8, 2014 and entitled“WellGauge,” the contents of which are hereby incorporated by referencein their entirety.

FIELD

The subject matter disclosed herein relates to equipment used todetermine the water depth in a well.

BACKGROUND

Measuring the water level in a water well may allow identification ofwell-production problems before they cause further problems such aswater outages and pump damage. Some drinking water rules require watersystems to maintain records of static well-water levels on a seasonalbasis including low demand and high demand periods. Issues that causereduced well production may include: bacterial growth or mineraldeposits that plug well casing slots or screens; over-pumping that maycause a drop in the aquifer level; and/or problems with the operation ofthe well pump or pump motor. Periodically measuring the static waterlevel and the pumping water level over a number of years may reveal anyseasonal variations to water levels in the aquifer, and show trends onhow the well performs.

SUMMARY

Methods, apparatuses, and computer readable medium including computerprogram products, are provided for determining the depth of water in awell. A method may include coupling a signal onto a cable connected to asubmersible well pump. The method may further include monitoring thecable to determine a first time corresponding to a first reflection ofthe signal caused by the cable entering a water column between a watersurface and the submersible pump. The method may further includemonitoring the cable to determine a second time corresponding to asecond reflection of the signal caused by an impedance mismatch betweenthe cable surrounded by water and a motor in the submersible well pump.The method may further include determining a water height between thesubmersible pump and the water surface from the first time and thesecond time.

In some variations, one or more of the features disclosed hereinincluding the following features can optionally be included in anyfeasible combination. The method may include determining the waterheight from a difference between the first time and the second time,wherein the water height is a distance in the water column between thesubmersible pump and the water surface. The method may further includedetermining based on the first time a cable length between a pointcorresponding to the launching of the signal and the water surface. Themethod may further include determining based on the second time a cablelength between a point corresponding to the launching of the signal andthe motor in the submersible pump. The signal may include a voltagestep. The cable may include a power cable providing power to thesubmersible pump. The water height may be sent wirelessly to at leastone of a user equipment or a computer. The cable may be insulated. Thecable may include one or more metal conductors.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive. Further features and/or variations may beprovided in addition to those set forth herein. For example, theimplementations described herein may be directed to various combinationsand subcombinations of the disclosed features and/or combinations andsubcombinations of several further features disclosed below in thedetailed description.

The above-noted aspects and features may be implemented in systems,apparatuses, methods, and/or computer-readable media depending on thedesired configuration. The details of one or more variations of thesubject matter described herein are set forth in the accompanyingdrawings and the description below. Features and advantages of thesubject matter described herein will be apparent from the descriptionand drawings, and from the claims.

DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, show certain aspects of the subject matterdisclosed herein and, together with the description, help explain someof the principles associated with the subject matter disclosed herein.In the drawings,

FIG. 1A depicts a submersible pump suspended from a drop pipe in a wellcasing, in accordance with some example embodiments;

FIG. 1B depicts an exploded view of a well head, in accordance with someexample embodiments;

FIG. 2 depicts an example signal waveform, in accordance with someexample embodiments;

FIG. 3 depicts an example of a process, in accordance with some exampleembodiments;

FIG. 4 depicts an example of an apparatus, in accordance with someexample embodiments; and

FIG. 5 depicts an example screenshot from a user interface, inaccordance with some example embodiments.

Like labels are used to refer to same or similar items in the drawings.

DETAILED DESCRIPTION

The subject matter disclosed herein relates to determining the depth ofwater in a water well. A water well may be drilled to a sufficient depthto cause water to enter a well casing extending from the bottom of thewell to the earth's surface. For example, a water well may drilled to adepth of 150 feet and a well casing may have an eight inch diameter. Insome example embodiments, a submersible pump may be suspended in thewell casing. The pump may be suspended from a drop pipe of smallerdiameter than the casing. For example, the drop pipe may be one inch indiameter. The submersible pump may be suspended at a pump height abovethe bottom of the well to reduce or prevent sediment from the bottom ofthe well from being drawn into the submersible pump. For example, thesubmersible pump may be suspended 20 feet from the bottom of the well.Water enters the well and fills the well casing with water to a waterheight. The depth of water in the well casing available to pump to astorage tank or for use by a water user is the water in the well casingbetween the pump height and the water height. Water below the pumpheight may not be available to the submersible pump because thesubmersible pump water inlet may be at the pump height.

Although the previous example describes the pump power cable carryingthe launched signal, other types of cables may also carry the launchedsignal. For example, a signal cable may be used that extends through thewater surface to the submersible pump or other device associated withthe pump. The cable may include one or more metallic conductors,non-metallic conductors, or optical fibers may be used as well. In someexample embodiments, one or more conductors may be insulated ornon-insulated.

In some example embodiments, the difference in height between the pumpheight and the water height may be determined from a signal launched ona cable, or coupled to the cable, running from the submersible pump toat least the water height in the casing. For example, the submersiblepump may be electrically powered via a power cable extending from thetop of the well at the well cap. The signal may be launched or coupledto the power cable so that the power cable carries the launched signalin addition to providing power to the pump. In some example embodiments,the distance between the pump height in the casing and the water heightin the casing may be determined from a first reflection of the launchedsignal due to an impedance mismatch at the water height, and a secondreflection due to an impedance mismatch at the submersible pump height.The time difference between the first reflection and the secondreflection may correspond to the height of the water between the top ofthe water in the casing and the submersible pump positioned deeper inthe casing. In this way, the height of the water column in the wellcasing that is available to be pumped by the submersible pump may bemonitored over time. For example, a homeowner may monitor the height ofthe available water column over hours, days, weeks, months, and/oryears.

In some example embodiments, the current drawn by the submersible pumpmotor may be monitored via a series shunt placed in the power line tothe pump. The voltage across the shunt may be representative of thecurrent consumed by the motor. In some example embodiments, the currentconsumed by the motor over time may be monitored. In some embodiments, alevel switch or pressure switch may be included with a storage tank. Thelevel switch or pressure switch may cause the pump to run when the tankis not full or at a prescribed height. The run time of the motor betweenwhen the level switch or pressure switch causes the pump to run to whenthe level switch or pressure switch causes the pump to stop may bemonitored over time as a pump motor runtime.

In some example embodiments, an existing cable used to power thesubmersible pump may be used in accordance with the foregoing todetermine the height of the available water column in the well, and tomonitor the current draw and run time of the pump over periods of timeto monitor the health of the well and the pump. In some exampleembodiments, installation of an apparatus consistent with the foregoingis simplified, safer, less intrusive, and less expensive because theexisting power cable to the pump may be used to determine the height ofthe available water column.

FIG. 1A depicts a submersible pump suspended from a drop pipe in a wellcasing, in accordance with some example embodiments. FIG. 1B depicts anexploded view of the well head 110, in accordance with some exampleembodiments. Well head 110 may be attached to the top of the well casing130. Submersible pump 150 may be submerged in water and may be attachedto the bottom of drop pipe 140. Pump power cable 120 may run from wellhead 110 to submersible pump 150.

Well head 110 may be located at the top of well casing 130. Well head110 may include cap 112 to cover the top of well casing 130 and enclosemonitoring electronics 111. Monitoring electronics 111 may include abattery that may be used to power the monitoring electronics. An inputpower cable 118 may enter well cap 112 to provide source power tosubmersible pump 150. In some embodiments, input power cable 118 may beplaced inside a conduit such as polyvinyl chloride (PVC) conduit 116 toprotect the input power cable from damage as may be required by buildingcodes. Electrical connection may be made between the input power cable118 and the pump power cable 120. Monitoring electronics 111 inside thecap 112 may also connect to input power cable 118 and pump power cable120. For example, the battery in monitoring electronics 111 may becharged when electrical power is provided at input power cable 118. Insome embodiments, submersible pump 150 may include a 120 voltalternating current (VAC) pump. A pump motor using any other alternatingcurrent or direct current voltage may be used as well. In this example,when 120 VAC is provided on input power cable 118, a battery chargerthat is part of monitoring electronics 111 may charge the battery aswell as provide power to the monitoring electronics 111 and pump 150.When no power is supplied on input power cable 118, the monitoringelectronics 111 may be powered by the battery.

Pump power cable 120 may run from the monitoring electronics 111 locatedin cap 112, through well casing 130, to submersible pump 150. Powerflowing from the input power cable through the cap 112 and monitoringelectronics 111 to submersible pump 150 may cause submersible pump 150to pump water surrounding the pump into drop pipe 140. Water may besupplied to a tank, house, and/or water user through drop pipe 140. Insome example embodiments, pump power cable 120 may be attached to theexterior of drop pipe 140.

Pump power cable 120 may include two, three, or more solid or strandedwires. Each wire may include an insulating jacket. For example the wiresmay have jackets made of polyvinyl chloride (PVC), polyethylene (PE),polypropylene (PP), polyurethane (PUR), chlorinated polyethylene (CPE),Teflon, silicone, rubber, or any other electrically insulating material.The insulated wires may be twisted together. The pump power cable 120may include an outer jacket that surrounds the insulated wires in asecond insulating outer jacket. For example, pump power cable 120 mayinclude two wires, and the like. In this example each wire may havepolyethylene insulation around the wire. Continuing the example, the twoinsulated wires may have a polyethylene jacket surrounding the twoinsulated wires. Although the previous example describes two insulatedwires that are not twisted together inside an outer insulating jacket,other types of cables that include insulated wires that are twistedtogether with or without an outer jacket may be used as well.

In some example embodiments, the wires may be arranged to be inproximity to each other which may cause a characteristic impedancebetween the wires. In some example embodiments, electromagnetic fieldsmay couple energy between the wires. The electromagnetic fields may bepresent in the insulating jackets surrounding each wire. Theelectromagnetic fields may extend into the outer jacket surrounding thetwo (or more) wires. The electromagnetic fields may extend beyond theouter jacket into the surrounding space. The characteristic impedancemay be determined at least in part by the proximity of the wires, theinsulation surrounding each wire, whether the wires are twistedtogether, whether there is an outer jacket, and/or the mediumsurrounding the wires (e.g. air, water, or some other liquid). In theprevious example, if the two wires do not have a surrounding jacket butare twisted together, electromagnetic fields may couple the two wirescreating a characteristic impedance that may be the same or differentfrom the characteristic impedance when the two wires have an outerinsulating jacket.

In some example embodiments, a voltage step may be generated or inducedon the pump power cable 120 by monitoring electronics 111. The voltagestep may propagate along the pump power cable 120 toward the submersiblepump 150. Continuing the previous example, the characteristic impedanceof the cable may be determined by at least the polyethylene jacketaround each wire, the outer polyethylene jacket around both wires,whether the two wires are twisted inside the outer jacket, and themedium outside the outer jacket. Continuing the previous example, themedium outside the outer jacket may be air between the cap 112 and thesurface of the water in the well casing 130 causing a firstcharacteristic impedance. At the water height in the well casing, themedium surrounding the pump power cable 120 may change from air towater. The change in medium surrounding the pump power cable 120 maycause a change in the characteristic impedance of the pump power cable.The change in characteristic impedance of the pump power cable may causea reflection of a portion of the voltage step generated by themonitoring electronics 111. The reflected voltage step may propagateback toward the monitoring electronics where the monitoring electronics111 detects the reflected step. A time may be recorded corresponding tothe arrival of the first reflected step from the impedance mismatchcaused where the pump power cable enters the water. In some exampleembodiments, the time between when the step was launched at themonitoring electronics 111 and the arrival of the first reflectedvoltage step corresponds to the time taken for the voltage step topropagate from the monitoring electronics 111 to the surface of thewater and back. The distance or length of the pump power cable 120between the monitoring electronics 111 and the surface of the water inthe well casing may be determined from a difference between the time ofthe launched voltage step and the arrival time of the first reflectedstep. The difference in time may be referred to as a propagation time.The speed of the signal propagating along the pump power cable may beknown by calibration or may be approximated based on the type of cable.Using the speed of propagation and the time between the launched signaland the reflected signal described in the foregoing, a distancecorresponding to the time may be determined.

A portion of the voltage step may continue to propagate along the pumppower cable 120 toward the motor in the submersible pump 150. In someexample embodiments, the motor in the submersible pump may have adifferent impedance from the characteristic impedance of the pump powercable 120 surrounded by the water in the well casing. The differentimpedance of the pump motor compared to the pump power cable surroundedby water characteristic impedance may cause a second reflection of thevoltage step that may propagate back to monitoring electronics 111. Thesecond reflection may be detected by the monitoring electronics 111. Insome example embodiments, the time between when the step was launched atthe monitoring electronics 111 and the arrival of the second reflectedvoltage step corresponds to the time taken for the voltage step topropagate from the monitoring electronics 111 to the motor in thesubmersible pump 150 and back. The distance or length of the pump powercable 120 between the monitoring electronics 111 and the submersiblepump motor may be determined from a difference between the time of thelaunched voltage step and the arrival time of the second reflected step.

The height of the water column available for the submersible pump 150 topump out through drop pipe 140 corresponds to the time differencebetween the arrival times at monitoring electronics 111 of the firstreflection and the second reflection. The difference in time between thearrival of the first and second reflections corresponds to theround-trip transit time along the pump power cable through the watercolumn between the surface of the water and the motor in the submersiblepump 150.

Cap 112 may mechanically interface to adapter sleeve 114 to adapt thewell cap 112 to different well casing 130 diameters. For example, wellcap 112 may accommodate casing diameter up to a predetermined size, suchas 6 inches (although other sizes may be used as well). An adaptersleeve 114 may be used to adapt an 8 inch well cap 112 to a 6 inch, 8inch, and/or 10 inch well casing 130 diameter. Any other diameter ofwell cap and/or well casing may also be used by modifying adapter sleeve114.

Well casing 130 may comprise a tube made of one or more materials. Forexample, well casing 130 may comprise a metal tube near the earth'ssurface to provide structural rigidity to the well components. Part waydown the casing the material may be changed to another material such asPVC or any other material. In some example embodiments the well casingmay comprise the same material from the ground surface to the bottom ofthe well. Well casing 130 may have any diameter such as 6 inch, 8 inch,12 inch, or any other diameter.

Drop pipe 140 may comprise a tube made of one or more materials. Forexample, drop pipe 140 may comprise a polyethylene tube from the wellcap to the submersible pump. In some example embodiments the drop pipemay change materials at some point between the cap 112 and submersiblepump 150. Fittings may be used to adapt the drop pipe to the submersiblepump 150. Drop pipe 140 may have any diameter smaller than the wellcasing. For example, the drop pipe may be one inch in diameter.

Submersible pump 150 may include any type of alternating current ordirect current motor coupled to a pump. In some example embodiments, themotor in submersible pump 150 may be a 220 VAC motor. In some exampleembodiments, the motor may be a 24 VDC motor, although motors operatingat other voltages also may be used.

FIG. 2 depicts an example waveform at the monitoring electronics, inaccordance with some example embodiments. FIG. 2 refers to FIG. 1. Avoltage step may be launched at the monitoring electronics 111 at 210.The voltage step may propagate along the pump power cable 120 toward themotor in the submersible pump 150. At 220, a first reflectioncorresponding to a reflection from the water surface may arrive at themonitoring electronics at a later time determined by the length of thepump power cable between the monitoring electronics and the surface ofthe water in the well casing 130. At 230, the second reflectioncorresponding to a reflection from the pump motor may arrive at themonitoring electronics at a time later than the first reflection. Thelater arrival time of the second reflection may be determined at leastin part by the length of the pump power cable between the monitoringelectronics and the motor.

At 210, monitoring electronics 111 may launch a voltage step onto thepump power cable 120. The voltage step may propagate along the pumppower cable 120 toward the motor in the submersible pump 150. Thevoltage step may have a rise time of about one to ten nanoseconds. Thevoltage step rise time may be selected based on an accuracy and/orresolution needed in the determination of the water column height abovethe submersible pump 150. For example, slower rise times may correspondto less accuracy and/or resolution of the distances between themonitoring electronics and the water height, and between the monitoringelectronics height and pump height. For example, a rise time slower thanone nanosecond may correspond to an accuracy and/or resolution ofgreater than approximately one foot. Faster rise times may correspond toan accuracy and/or resolution of less than approximately one foot.Although the forgoing discloses using a voltage step as the signal thatmay be reflected at the surface of the water in the well casing 130 andfrom the motor in the submersible pump 150, other signals shapes may beused as well. For example, the signal may include a pulse or impulsesuch as a Gaussian shaped pulse, triangular pulse, sinusoidal shapedpulse or any other shape.

At 220, a first reflection may be generated by an impedancediscontinuity at the point along the pump power cable 120 where thecable becomes submerged into the water in the well casing 130. In someexample embodiments, the first reflection of the step may cause areduction in the voltage of the step that propagates back to themonitoring electronics 111. For example, when the impedance of the pumppower cable 120 surrounded by air is greater than the characteristicimpedance of the pump power cable surrounded by water, the reflectionmay cause a decrease in the voltage of the step that propagates back tothe monitoring electronics. In the example of FIG. 2, the voltage at220corresponds to a reflected step from a lower characteristic impedancewhere the pump power cable enters the well casing water. The timedifference between 210 and 220 corresponds to the length of the pumppower cable between the monitoring electronics 111 and the surface ofthe water in the well casing.

At 230, a second reflection may be generated by an impedancediscontinuity between the power cable 120 below the water surface andthe motor in the submersible pump 150. In some example embodiments, thesecond reflection of the voltage step may cause an increase in thevoltage of the step that propagates back to the monitoring electronics111. For example, when the impedance of the motor in the submersiblepump 150 is greater than the characteristic impedance of the submergedpump power cable 120, the reflection causes an increase in the voltageof the step that propagates back to the monitoring electronics 111. Inthe example of FIG. 2, the voltage at 230 corresponds to a reflectedstep from a higher impedance motor than the submerged pump power cable120. The time difference between 220 and 230 corresponds to the lengthof the pump power cable 120 between the surface of the water in the wellcasing 130 and the motor in the submersible pump 150. Monitoringelectronics 111 initiates the voltage step that is coupled to the pumppower cable 120, detects the first and second reflections, anddetermines distances from the times that the reflections are receivedincluding the height of the water column between the submersible pumpand the surface of the water in the well casing.

FIG. 3 depicts an example of a process, in accordance with some exampleembodiments. FIG. 3 refers to FIGS. 1 and 2. At 310, a signal islaunched onto an insulated power cable that provides power to a wellpump. At 320, the voltage on the power cable is monitored to determine afirst reflection of the signal caused by a change of the mediumsurrounding the power cable 120 from air to water. At 330, the voltageon the pump power cable 120 is monitored to determine a secondreflection of the voltage step caused by the difference in impedancebetween the submerged power cable and the motor in the submersible pump150. At 340, the height of the water column between the submersible pump150 and the water surface in the well casing may be determined from adifference in the arrival times between the first reflection from thewater surface and the second reflection from the motor in thesubmersible pump.

At 310, a signal is launched onto an insulated power cable that providespower to a submersible pump 150. In some example embodiments, a voltagestep may be generated on the pump power cable 120 by monitoringelectronics 111. The voltage step may propagate along the pump powercable 120 toward the submersible pump 150. The characteristic impedanceof the cable may be determined by at least the jacket around each wire,whether there is an outer jacket around the wires, whether the wires aretwisted, and the medium outside the outer jacket. The medium outside theouter jacket may be air between the cap 112 and the surface of the waterin the well casing 130 causing a first characteristic impedance. At thewater height in the well casing, the medium surrounding the pump powercable changes from air to water. The change in medium surrounding thepump power cable 120 may cause a change in the characteristic impedanceof the pump power cable. The change in impedance of the pump power cable120 may cause a reflection of a portion of the voltage step generated bythe monitoring electronics 111 that is propagating along the pump powercable 120.

At 320, the voltage on the power cable may be monitored to determine afirst reflection of the voltage step caused by the medium surroundingthe power cable changing from air to water. The reflected voltage stepmay propagate from a location corresponding to the water surface backtoward the monitoring electronics 111. The monitoring electronics 111may detect the reflected step as a first reflection. In some exampleembodiments, a time may be recorded corresponding to the arrival of thefirst reflection from the impedance discontinuity caused by the pumppower cable entering the water. In some example embodiments, the timebetween when the step was launched at the monitoring electronics 111 andthe arrival of the first reflection may correspond to the time taken forthe voltage step to propagate from the monitoring electronics 111 to thesurface of the water and back. The propagation time may correspond to acable length or distance between the monitoring electronics 111 and thewater surface.

At 330, the voltage on the power cable may be monitored to determine asecond reflection of the voltage step caused by the difference inimpedance between the submerged pump power cable 120 and the motor inthe submersible pump 150. A portion of the voltage step from themonitoring electronics may continue to propagate along the submergedpump power cable 120 toward the motor in the submersible pump 150. Insome example embodiments, the motor in the submersible pump may have adifferent impedance from the characteristic impedance of the pump powercable 120 surrounded by the water in the well casing. The differentimpedance of the pump motor compared to the pump power cable surroundedby water characteristic impedance may cause a second reflection of thevoltage step that may propagate back to monitoring electronics 111. Thesecond reflection may be detected by the monitoring electronics 111. Insome example embodiments, the time between when the step was launched atthe monitoring electronics 111 and the arrival of the second reflectedvoltage step corresponds to the time taken for the voltage step topropagate from the monitoring electronics 111 to the motor in thesubmersible pump 150 and back. The propagation time may correspond to acable length or distance between the monitoring electronics 111 and themotor in submersible pump 150.

At 340, the height of the water column available for the submersiblepump 150 to pump out through drop pipe 140 corresponds to the timedifference between the arrival at the monitoring electronics 111 of thefirst reflection and the second reflection. The difference in timebetween the arrival of the first and second reflections corresponds tothe round-trip transit time of the voltage step along the pump powercable 120 through the water column between the surface of the water andthe motor in the submersible pump 150. The round-trip transit timecorresponds to the distance between the surface of the water and thesubmersible pump (the height of the water column above the pump).

FIG. 4 depicts an apparatus, in accordance with some exampleembodiments. The description of FIG. 4 also refers to FIGS. 1-3. Theapparatus may include monitoring electronics such as monitoringelectronics 111 enclosed in a well cap such as cap 112. For example, theapparatus may include one or more processors 415, memory 416, a networkinterface such as WiFi module 414 or other wired or wireless interface,universal serial bus (USB) interface 413, battery 402, battery managerand charger 404, power supply 406, inductive isolator 408, pump motorvoltage and current monitor 410, shunt/current sensor 412, and stepgenerator, reflection receiver, and line coupler 418. Monitoringelectronics 111 may interface to an external or remote device 450 suchas a mobile phone or other computing device via the internet, wirelessnetwork, or wired network. Monitoring electronics 111 may include anytype of analog and/or digital electronics. For example monitoringelectronics 111 may include discrete electronic components (e.g.resistors, capacitors, inductors, transistors, and the like),amplifiers, comparators, mixers, oscillators, analog-to-digitalconverters, digital-to-analog converters, processors, memory, and/or anyother electronic component. The one or more processors 415 may be usedto calculate time differences between the launched signal and receivedreflections, and/or calculate lengths, distances, and/or heights fromtimes. The one or more processors and memory may be used to generate auser interface such as a web page that may be accessed via a wireless orwired network. In some embodiments, the monitoring electronics 111 maybe located outside the cap 112 such as in a garage, outbuilding, house,or enclosure.

Step generator, reflection monitor, and line coupler 418 may includecircuitry to generate a voltage step that may be launched or coupledonto the pump power cable 120. In some example embodiments, the voltagestep signal may be injected/coupled onto the well pump power cable 120through a high-pass filter that allows the fast rise time pulses to passwhile preventing the low-frequency alternating current power frompassing. In some example embodiments, a low-pass filter may be insertedinto the well pump power line 120 between the power source and where thevoltage step is injected onto the power cable 120. The low-pass filtermay prevent the fast rise-time voltage step from propagating towards thepower source which may cause erroneous reflections. Step generator,reflection monitor, and line coupler 418 may include circuitry tomonitor the pump power cable for reflections such as reflections fromthe water surface and the pump motor. Step generator, reflectionmonitor, and line coupler 418 may include any type of analog and/ordigital circuit component such as the above-noted circuit components.Although the forgoing discloses using a voltage step as the signal thatmay be reflected at the surface of the water in the well casing and fromthe submersible pump motor, other signals shapes may be used as well.For example, the signal may include a pulse or impulse such as aGaussian shaped pulse, triangular pulse, sinusoidal shaped pulse or anyother shape.

Current sensor/shunt 412 may be used to monitor the current drawn by themotor in the submersible pump. The current draw may be recorded overtime and may be used as an indicator to detect faults in the motorand/or pump. The motor runtime needed between a time when a float switchin a storage tank causes the pump to turn-on and the time the floatswitch causes the pump to turn-off may be recorded as a motor runtime.The motor runtime may be recorded over time and may be used as anindicator of a fault in the motor and/or pump. For example, if the motorruntime has increased over time the pump may be performing lessefficiently due to clogging by debris, or the motor may be runninglonger due to a failing motor.

In some example embodiments, processor 414 and memory 416 may generate auser interface from which the water height in the well casing, motorcurrent draw history, and/or motor runtime history may be viewed. Insome example embodiments, commands may be issued via the user interfaceto cause the changes in the monitoring electronics and/or userinterface.

FIG. 5 depicts an example screenshot from a user interface, inaccordance with some example embodiments. FIG. 5 refers to FIGS. 1-4.User interface screen 500 may include the water height 505 which maydisplay the height of the water column between the submersible pump 150and the surface of the water in the well casing 130. The user interfacescreen 500 may further include the motor runtime 510 which may displaythe submersible pump runtime over a predetermined time period such as anhour, a day, a week, and so on. The motor runtime may be an averageruntime over more than one day, may be a maximum motor runtime, minimumruntime, or other indicator of runtime. The user interface screen 500may further include the motor current draw 515 which may display thesubmersible pump current draw over a predetermined time period such asan hour, a day, a week, and so on. The motor current draw may be anaverage current draw over more than one day, may be a maximum currentdraw, minimum current draw, or other indicator of current draw. The userinterface screen 500 may further include timestamp 520 indicating acurrent date and/or time, a date and/or time when the pump was last run,and so on.

User interface screen 500 may include any type of graph showing ahistory of water height at 530, a motor runtime history at 540, and/ormotor current draw history 550. Other graphs or representations of thewater height, motor runtime, and/or motor current draw may be generatedat user interface screen 500. In some example embodiments, commands maybe sent to monitoring electronics 111 via the user interface screen 500(commands are not shown in FIG. 5). For example, a command may be sentto clear one or more histories, set alarm levels, cause automaticuploads of pump and well data to a file transfer protocol (ftp) site,configure an electronic notification, as well as other commands. Forexample, a user may set an alarm to generate an email and/or textmessage when the water height drops below a configured height, forexample 15 feet. Monitoring electronics 111 may generate and send anemail and/or text message to at address configured in the electronicnotification.

In some example embodiments, user interface screen 500 may be accessiblevia any computing device connected to the internet and/or a privatenetwork. For example, a smartphone connected to the internet may accessinterface screen 500 by accessing an appropriate uniform resourcelocator (URL). In some example embodiments, a user may be required to beauthenticated via a username and/or password before access to the wellpump user interface screen 500.

Although the forgoing description has been directed toward a depth ofwater in a water well, the same methods/apparatuses may be used todetermine the depth of water in a tank. In some example embodiments,instead of water another liquid may be used. For example, the liquid ina well or tank may be oil, fuel, or any other liquid.

The subject matter described herein may be embodied in systems,apparatus, methods, and/or articles depending on the desiredconfiguration. For example, the monitoring electronics disclosed hereincan be implemented using one or more of the following: a processorexecuting program code, an application-specific integrated circuit(ASIC), a digital signal processor (DSP), an embedded processor, a fieldprogrammable gate array (FPGA), and/or combinations thereof. Thesevarious implementations may include implementation in one or morecomputer programs that are executable and/or interpretable on aprogrammable system including at least one programmable processor, whichmay be special or general purpose, coupled to receive data andinstructions from, and to transmit data and instructions to, a storagesystem, at least one input device, and at least one output device. Thesecomputer programs (also known as programs, software, softwareapplications, applications, components, program code, or code) includemachine instructions for a programmable processor, and may beimplemented in a high-level procedural and/or object-orientedprogramming language, and/or in assembly/machine language. As usedherein, the term “machine-readable medium” refers to any computerprogram product, computer-readable medium, computer-readable storagemedium, apparatus and/or device (e.g., magnetic discs, optical disks,memory) used to provide machine instructions and/or data to aprogrammable processor, including a machine-readable medium thatreceives machine instructions. Similarly, systems are also describedherein that may include a processor and a memory coupled to theprocessor. The memory may include one or more programs that cause theprocessor to perform one or more of the operations described herein.

Although a few variations have been described in detail above, othermodifications or additions are possible. In particular, further featuresand/or variations may be provided in addition to those set forth herein.Moreover, the implementations described above may be directed to variouscombinations and subcombinations of the disclosed features and/orcombinations and subcombinations of several further features disclosedabove. In addition, the logic flow depicted in the accompanying figuresand/or described herein does not require the particular order shown, orsequential order, to achieve desirable results. Other embodiments may bewithin the scope of the following claims. Furthermore, the specificvalues provided in the foregoing are merely examples and may vary insome implementations.

Although various aspects of the invention are set out in the independentclaims, other aspects of the invention comprise other combinations offeatures from the described embodiments and/or the dependent claims withthe features of the independent claims, and not solely the combinationsexplicitly set out in the claims.

It is also noted herein that while the above describes exampleembodiments of the invention, these descriptions should not be viewed ina limiting sense. Rather, there are several variations and modificationswhich may be made without departing from the scope of the presentinvention as defined in the appended claims.

What is claimed is:
 1. A method comprising: coupling a signal onto acable connected to a submersible well pump; monitoring the cable todetermine a first time corresponding to a first reflection of the signalcaused by the cable entering a water column between a water surface andthe submersible pump; monitoring the cable to determine a second timecorresponding to a second reflection of the signal caused by animpedance mismatch between the cable surrounded by water and a motor inthe submersible well pump; and determining a water height between thesubmersible pump and the water surface from the first time and thesecond time.
 2. The method of claim 1, wherein the water height isdetermined from a difference between the first time and the second time,and wherein the water height is a distance in the water column betweenthe submersible pump and the water surface.
 3. The method of claim 1,wherein a cable length between a point corresponding to the launching ofthe signal and the water surface is determined based on the first time.4. The method of claim 1, wherein a cable length between a pointcorresponding to the launching of the signal and the motor in thesubmersible pump is determined based on the second time.
 5. The methodof claim 1, wherein the signal comprises a voltage step.
 6. The methodof claim 1, wherein the cable comprises a power cable providing power tothe submersible pump.
 7. The method of claim 1, wherein the water heightis sent wirelessly to at least one of user equipment or a computer. 8.The method of claim 1, wherein the cable is insulated.
 9. The method ofclaim 1, wherein the cable comprises one or more metal conductors. 10.The method of claim 1, wherein the coupling the signal onto the cable,the monitoring the cable to determine the first time, and the monitoringthe cable to determine the second time are performed at a well head. 11.An apparatus comprising: a coupler to couple a signal onto a cableconnected to a submersible well pump; a monitor to monitor the cable todetermine a first time corresponding to a first reflection of the signalcaused by the cable entering a water column between a water surface andthe submersible pump, wherein the monitor further determines a secondtime corresponding to a second reflection of the signal caused by animpedance mismatch between the cable surrounded by water and a motor inthe submersible well pump; and a calculator to determine a water heightbetween the submersible pump and the water surface from the first timeand the second time.
 12. The apparatus of claim 11, wherein the waterheight is determined from a difference between the first time and thesecond time, and wherein the water height is a distance in the watercolumn between the submersible pump and the water surface.
 13. Theapparatus of claim 11, wherein a cable length between a pointcorresponding to the launching of the signal and the water surface isdetermined based on the first time.
 14. The apparatus of claim 11,wherein a cable length between a point corresponding to the launching ofthe signal and the motor in the submersible pump is determined based onthe second time.
 15. The apparatus of claim 11, wherein the signalcomprises a voltage step.
 16. The apparatus of claim 11, wherein thecable comprises a power cable providing power to the submersible pump.17. The apparatus of claim 11, wherein the water height is sentwirelessly to at least one of a user equipment or a computer.
 18. Theapparatus of claim 11, wherein the cable is insulated.
 19. The apparatusof claim 11, wherein the cable comprises one or more metal conductors.20. The apparatus of claim 11, wherein the coupling the signal onto thecable, the monitoring the cable to determine the first time, and themonitoring the cable to determine the second time are performed at awell head.
 21. A non-transitory computer-readable medium encoded withinstructions that, when executed by at least one processor, causeoperations comprising: coupling a signal onto a cable connected to asubmersible well pump; monitoring the cable to determine a first timecorresponding to a first reflection of the signal caused by the cableentering a water column between a water surface and the submersiblepump; monitoring the cable to determine a second time corresponding to asecond reflection of the signal caused by an impedance mismatch betweenthe cable surrounded by water and a motor in the submersible well pump;and determining a water height between the submersible pump and thewater surface from the first time and the second time.